Fire, smoke, and heat detector/alarm systems in residential and commercial buildings are able to save lives and are required to be installed by building codes. Many different types of such systems are in use and are designed to meet the needs of various kinds of installations. Residential installations typically rely upon smoke detectors, which respond to the presence of airborne smoke particles. However, smoke detectors can be unreliable and falsely activated in commercial and industrial environments due to the presence of other airborne materials, such as vapors and dusts produced in the normal course of commercial and industrial activity. As a result, many commercial and industrial installations use heat detectors which are activated by certain changes in temperature indicative of a possible fire.
Many heat detectors are either a rate compensated type or operate on the rate of rise principle. These types of detectors are capable of sensing an elevated temperature and/or a rate of rise of air temperature surrounding the detector. The temperature of air near a ceiling tends to rise rapidly in the event of a fire, and heat detectors incorporating the rate of rise or rate compensation feature are designed to respond to rapid rises in temperature in order to discriminate between more gradual temperature increases unrelated to fire incidents. Rate compensated heat detectors can be a combination of a fixed temperature and a rate anticipation detector, meaning such detectors can also activate an alarm simply upon reaching a given temperature during slow heat rise. During rapid heat rise, however, they may be designed to recognize a temperature lag between the detector temperature and air temperature. The temperature of the heat detector unit will lag behind rapidly rising temperature of surrounding air because of the time required for heat to transfer from the ambient air to the heat sensor unit. The extent of the lag depends on how quickly the air temperature rises. Lag may be greater for a more rapid air temperature rise. Rate compensated heat detectors are constructed to compensate for this temperature lag, so as to trigger an alarm at a lower detector temperature if the temperature of the detector is rising rapidly, and trigger the alarm at a higher detector temperature if the rate of rise is slower.
Various types of heat detectors are available with various temperature ratings to respond to different temperature ranges. Each heat detector also has a radius of effective coverage. This radius may vary from one heat detector model to another. A typical installation requires a certain number of heat detectors per square foot be installed on a ceiling of the structure to be protected. The spacing between the detectors is determined by the effective coverage capability of each unit. A large commercial or industrial space, such as a warehouse, may have a considerable number of heat detectors. Furthermore, such spaces commonly have high ceilings, which places the heat detectors out of easy reach.
Often, operational testing of heat detectors, if such testing is done at all, is accomplished with makeshift methods or heat sources. Commonly employed heat sources may include heat guns and heat lamps. A ladder may be placed under each heat detector and the heat source can then be carried by hand up the ladder to test the detector. Long extension cords may be required for this approach. This can be time consuming, inefficient, and ineffective for testing heat detectors. Other detector testing means include using a soldering iron or heated water and can present significant safety concerns. A need therefore exists for a safe, efficient and reliable method for testing heat detector installations.